Related Experiment Videos
Twins and chronogenetics: correlated pathways of development
Insights
Infant twin development shows high synchronization in physical growth and mental development separately. However, growth spurts and lags in physical and mental domains occur independently, not in sync.
Area of Science:
- Developmental Psychology
- Behavioral Genetics
Background:
- Understanding synchronized development in twins is crucial for discerning genetic and environmental influences.
- Previous research suggests potential links between physical growth and cognitive development trajectories.
Purpose of the Study:
- To investigate the synchronization of physical growth and mental development in infant twins.
- To determine if growth spurts and lags in physical and mental domains occur concurrently or independently.
Main Methods:
- Longitudinal study of monozygotic (MZ) twins from 3 months to 6 years.
- Analysis of height and mental development measures for twin concordance and cross-domain correlation.
Main Results:
- High twin concordance observed separately for physical growth and mental development.
- Low correlation found between physical and mental development measures, indicating independent timing of growth spurts and lags.
Conclusions:
- Physical growth and mental development episodes are largely independent in timing during early childhood.
- Highly synchronized genetic factors likely regulate distinct developmental pathways for physical and mental growth.
Abstract:
Developmental processes in infant twins are considered from the standpoint of how closely synchronized the twins are for growth spurts and lags, and whether the course of mental development follows the same trajectory as physical growth. The episodes of acceleration and lag may be independent for the two domains, so than an infant who is precocious in physical growth may not necessarily be advanced in mental development. The phasing of maturational episodes appears to depend upon timed gene-action systems which unfold in sequential order, and which promote new behavioral capabilities as well as physical growth. Data are reported from a large sample of MZ twins that were followed from 3 months to 6 years of age, with measures made of height and mental development. The measures were analyzed separately for the degree of twin concordance over ages, as an indicator of how closely the twins' growth spurts were synchronized. Then the measures were correlated to determine whether the episodes of acceleration and lag occurred at the same time for height and mental development, or were out of phase. The results showed only a low-order correlation among measures, indicating that the episodes of rapid growth and lag were essentially independent for the two domains. By contrast, the twin concordance was very high for each measure separately. The results are interpreted in the broader context of timed gene-action systems of extraordinary precision which initiate and regulate the episodes of growth.